1. Field of the Invention
The present invention relates to a polymer blend; more specifically, the present invention relates to a polymer blend with excellent transparency and softness in addition to excellent properties such as processability, weatherability, color developing property and colorability.
2. Description of the Background Art
Olefin polymers such as olefin resins and olefin elastomers show excellent moldability and softness, and by advantageously utilizing these properties, these polymers are commonly used as molding materials, singly or in combination with other thermoplastic resins, thermoplastic elastomers and softening agents by blending the thermoplastic resins, thermoplastic elastomers and softening agents with the polymers. Molded articles produced from olefin polymers include for example automobile bumpers and console panels. Because these olefin polymers do not contain any polar group, however, these polymers are poor in terms of coatability, printability and color developing property during coloring, so that colors and patterns are selected from a narrow range when these polymers are subjected to molding and post-treatment after molding. In other words, currently, the colors and patterns therefor are not freely selected. Although olefin polymers have softness, the surface hardness thereof is adversely so low that the polymers are poor in terms of resistance to scuffing. Because olefin polymers are thermoplastic and can therefore be recycled, however, it is desirable to promote the active use of olefin polymers while improving the drawbacks thereof as described above, from the respect of the current environmental circumstance where great significance is put to materials to be recycled.
Acrylic resins representatively illustrated by methacrylic resin can be recycled, because the resins are excellent in terms of properties including transparency, color developing property, weatherability, and surface hardness and can be decomposed as monomers on heating. Therefore, the acrylic resins are put to a variety of uses primarily including molding materials, for example, a variety of molded articles, window glass and covers of florescent tube, which are frequently used outdoors. However, acrylic resins with low impact resistance are generally poor in terms of softness, so it is desired to improve these properties of the resins.
As resin materials satisfying the demands for properties such as transparency, impact resistance and color developing property at some degree, ABS resin and impact resistant acrylic resins are known, but these resins have poor weatherability because diene rubber with an unsaturated bond in the primary chain thereof is used to improve impact resistance. As resin materials with improved weatherbility, alternatively, AES resin (A/EPDM/S copolymer) and acrylic resins with acrylate ester rubber dispersed therein are known. From the respect of the balance between demands for resin properties and cost, however, these resin materials have only limited utilities, essentially.
Because vinyl chloride polymers are inexpensive and adjustable of their hardness and mechanical properties, depending on the amount of a plasticizer to be blended therein, the polymers are widely used both in the field demanding high surface hardness and transparency like those of acrylic resins and in the field demanding low surface hardness and softness like those of olefin polymers. However, vinyl chloride polymers of themselves have so poor processability that the polymers are molded by using a vast amount of plasticizers. Therefore, the polymers have a serious problem in that the plasticizers used in the molded articles may bleed out onto the surface of the articles. Because vinyl chloride polymers are decomposed on heating to generate hazardous halogen containing compounds, the polymers can hardly be recycled, which currently involves serious concerns about the disposal management of waste plastics containing vinyl chloride polymers.